ACE5372

Low Power Real-Time Clock (RTC)

VER 1.3

4

7H

Time Trimming Register

Storing adjusting parameter and external select control of

crystal oscillator

8H

Alarm_A (Minute

Register)

Storing minutes in Timer A

9H

Alarm_A (Hour Register)

Storing hours in Timer A

AH

Alarm_A (Day of the

Week Register)

Storing days of the week in Timer A

BH

Alarm_B (Minute

Register)

Storing minutes in Timer B

CH

Alarm_B (Hour Register)

Storing hours in Timer B

DH

Alarm_B (Day of the

Week Register)

Storing days of the week in Timer B

EH

Control Register 1

Storing ring enable, interrupt output port select, and periodic

interrupt cycle select information

FH

Control Register 2

Storing time display select, interrupt and alarm signal,

oscillator halt sensing information

Calendar Counter

The ACE5372 can exchange from year to second (lower two bits) with CPU. When the lower two bits of

the year could be divided by 4, that year is leap year. It could automatically recognize the year between

2000 and 2099 and these data are stored separately in registers from 0H to 6H.

Control Unit

The control unit is a substantial part of the ACE5372, under which all functionalities of the whole circuit is

realized. The time display select, interrupt / alarm select and signal, output port select, as well as

oscillation halt sensing information are all sent out by the control circuit.

High Precision time Trimming function

The ACE5372 has an internal oscillation circuit capacitance CGND and CVDD so that an oscillation

circuit may be configured simply by externally connecting a crystal. The ACE5372 incorporates a time

trimming circuit (at internal address 7H) that adjusts gain or loss of the clock from the CPU up to

approx.±189ppm(±194ppm when 32.000KHz crystal is used) by approximately 3ppm steps to correct

discrepancy in oscillation frequency.

*Clock display is possible at much higher precision than conventional real-time clock while using a

crystal with broader fluctuation in precision.

* Even seasonal frequency fluctuation may be corrected by adjusting seasonal clock error.

For those systems that have temperature detection precision of clock, function may be increased by

correcting clock error according to temperature fluctuations.